Diverse rudist associations were widely distributed on the western margin of the Pelagonian microcontinent, now exposed in Boeotia, during the late Cretaceous, while only few caprotinid rudists and Radiolitidae have been found in marginal-marine and predominantly siliciclastic deposits of early Aptian to Cenomanian age.
Sixty-one rudist species of Aptian to Maastrichtian age are described, with emphasis on the delineation of intraspecific variability. Horiopleura? juxi sp. novo is described from Aptian conglomerates near Levadia. Praelapeirousia? sp. novo from Upper Turonian-?Coniacian limestones of the Ptoon Mountains is provisionally left in open nomenclature. A revision of Vaccinites cornuvaccinum (Bronn) is based on abundant material from Boeotia and several palaeontological collections, and includes the installation of a neotype.
Rudists are particularly abundant in Santonian-Campanian limestones that were deposited on top of karst-bauxites in southern Boeotia, and which overlie disconformably Triassic-Lower Cretaceous rocks in northern Boeotia. Vaccinites cornuvaccinum (Bronn) dominated among the Hippuritidae and thrived in protected subtidal lagoons as well as on landward slopes and probably on the crests of current-swept shoals. Different growth-strategies existed in environments with various rates of water agitation and sediment accumulation. Less adaptable Plagioptychidae and Radiolitidae were associated with V. cornuvaccinum in changing faunal compositions.
Diversity patterns of Greek rudists are similar to those of other Mediterranean regions and close affinities with faunas from Italy and the Dinarids are evident. The Greek associations can be attributed to either African or central Mediterranean faunal provinces, but provincial separation faded during periods of high sea-level.